Sunday, November 12, 2006

Towers and Birds

For some time, it has been known that communications towers pose a hazard for many species of birds. The problem is exacerbated when towers are placed in centers of migratory activity. Bird kills at towers tend to come from two causes. Sometimes birds will not see a portion of the tower, such as a guy wire or antenna. In other cases, birds are disoriented by a tower's lights and crash into the tower or the ground. The latter is a particular problem for nocturnal migrants.

Exact numbers of birds killed each year are difficult to determine because few towers are monitored. The Fish and Wildlife Service estimates 4-5 million on the basis of bodies recovered at a small sample of towers, but the number could well be much larger. At least 230 species are affected. Migrant songbirds are the primary victims of communication towers. This document (pdf) gives the top ten species killed.

  1. Ovenbird
  2. Red-eyed Vireo
  3. Tennessee Warbler
  4. Common Yellowthroat
  5. Bay-breasted Warbler
  6. American Redstart
  7. Blackpoll Warbler
  8. Black-and-White Warbler
  9. Philadelphia Vireo
  10. Swainson's Thrush
The Fish and Wildlife Service has been working with NGOs, industry representatives, and the Federal Communications Commission to develop regulations to reduce the problem. The FCC announced last week that a formal proposal is on the way. The proposed rules may follow existing guidelines from the FWS. These include:
  • Placement of new antennas on existing towers where possible rather than building new structures.
  • Keeping tower height under 200 feet, to avoid the need for lighting, and using self-supported structures rather guy wires.
  • Restricting towers within areas of major migratory activity.
  • Limiting lighting to the FAA minimum and using white strobe lights instead of red lights.
Unfortunately, it took a lawsuit from conservation groups to spur the FCC to act, but at least progress is being made on this issue. I will post a link to the proposed rules when they are published.

For more information